The present invention relates to an improved counter weight door.
Counter weighted overhead doors are well known and components for these doors are commercially available in many standard sizes. However when providing an counter weight overhead door for a large opening a number of problems arise. One of these problems is that conventional door components are designed for doors up to a certain size. These components and are not robust enough to handle the additional weight and forces required for a door covering a large opening. This requires that custom fittings and components be designed for individual doors which have openings which are too large to accommodated by standard sized components.
A second problem of overhead counter weight doors is that fixing and aligning the pulleys which guide the cables that are used to open and close the door is difficult since the pulleys are fixed to the wall of the building making positioning of the pulleys imprecise. Furthermore this often requires reinforcing a portion of the building to accept mounting brackets and fasteners to support the pulleys.
According to the present invention there is provided an improved counter weight door comprising:
a guide means arranged to be located on respective sides of an opening on a building;
a door which is arranged to be supported on respective side thereon by the guide means, the door having a plurality of panels each connected to the next one of the panels for common movement vertically in the guide means;
a counter weight system coupled to the door for providing counter weight for the weight of the door, the counter weight system having a plurality of counter weights each associated with a respective one of the panels;
an interconnecting means connecting each of the weights to the next;
the counter weight system having means for adjusting the weight of at least one of the counter weights;
wherein the counter weights having a support means which is arranged to receive a plurality of weighted members.
Conveniently the means for adjusting the weight having a changeable counter weight member which provides an appropriate weight for the counter weight such that the weight is relative each respective panel and door type.
Preferably each counter weight has a housing having a substantially flat bottom surface, side walls extending vertically from respective ends of the bottom surface, the bottom surface provides the support for the plurality of weighted members.
Preferably the counter weights are arranged to be stacked one on top of the next when the door is fully opened and spaced apart vertically when the door is fully closed.
According to another aspect of the present invention the interconnecting means provides a spring arrangement connecting one counter to the next.
Conveniently the spring arrangement is located with an enclosure within the counter weight.
Preferably the spring arrangement has a shaft located within a centre enclosure of the counter weight, the shaft being vertically orientated and has a horizontal flange at the top end within the enclosure, a spring surrounds the shaft and engages the flange and a bottom surface of the counter weight such that the spring forces the shaft upwards.
Conveniently an elongate member is coupled to a bottom end of the shaft and extends downwards therefrom to a respective counter weight below.
According to another aspect of the door there is provided a pulley system having;
a first pulley mounted adjacent a first side of the door;
a second guide pulley mounted adjacent the second side of the door;
a first elongate member fixed at a first end to the door extending through the first pulley;
a second elongate member fixed at a first end to the door extending through the second pulley;
wherein the second pulley arrangement has two pulleys in a fixed rotatable relationship for receiving the first and second elongate members, the elongate members extend through a third pulley at the counter weight system and are anchored at a second end.
An advantage of the present invention is provided by a driveable member on the second pulley which is arranged to be driven by a motor such that the door is raised and lowered using a motor.
Preferably the driveable member is a sprocket arranged to receive a chain from the motor.
An advantage of the present invention is that the door can be completely produced in a factory and simply assembled on site.